As programming approaches and foundations have evolved, application programming interfaces (APIs) and programming schemas have been developed to standardize and unify programming methodologies that were previously multi-variant and relatively incompatible. Modern programming therefore often involves employing APIs and schemas in conjunction with reusable libraries. Unfortunately, this evolution has inadvertently created many inefficient programming artifacts that are actually spread and perpetuated by these standardizations programming constructs. For example, one resulting software programming artifact is a duality between reference types and value types.
Reference types are variables that are stored on a heap and referenced by a pointer stored on the stack. Value types are variables that are stored directly on the stack. Consequently, variables that are represented as reference types can be uninitialized (termed “null”), but variables that are represented as value types cannot be established in an uninitialized condition without risking indeterminate or even catastrophic results. This nullification issue can present problems in a myriad of situations, including data base accessing.
The nullification problem has been previously addressed with many different strategies. Examples of such strategies include tuples, boxing, variants, convoluted pointer manipulations, and so forth. However, each of these strategies have one or more drawbacks including memory inefficiencies, runtime inefficiencies, loss of strong typing, proliferation of non-standard types, and so forth. By way of example, boxing turns value types into reference types, with the accompanying greater memory usage and increased processing demands to handle the inherent pointer overhead.
Support for nullability across all types, including value types, is essential when interacting with databases, yet general purpose programming languages have historically provided little or no support in this area. Many approaches exist for handling nulls and value types without direct language support, but all have shortcomings. For example, one approach is to use a “special” value (such as −1 for integers) to indicate null, but this only works when an unused value can be identified. Another approach is to maintain boolean null indicators in separate fields or variables, but this doesn't work well for parameters and return values. A third approach is to use a set of user-defined nullable types, but this only works for a closed set of types.